BEIJING, Aug. 31 (Xinhua) -- A London-based environmental advocate warned Monday that preying on sharks merely for the fins will not only harm the ecological system, but may also be bad for the health of consumers.

    Steve Trent, president of U.S.-headquartered Wild Aid, said it was important for China, the world's largest consumer of shark fins, to promote public awareness of the protection of this animal which is feared on the verge of extinction.

    Eating the fins may also be dangerous, said Trend, who also heads the Wild Aid's London Office. Research shows they contain heavy metals such as mercury, which can cause damage to the nervous system and male infertility.

    Wild Aid is dedicated to the protection of wildlife. Trent said China needed to make known to the public the ecological effects when sharks were killed in an unrestrained manner.

    Trent said hunting of sharks should be carried out in a sustainable way, restraint should be exercised in consumption of the cartilaginous fish, and the practice of hunting sharks merely for fins should be banned.

    Most Chinese were not aware their eating habits may have caused a negative impact on the ecological system and that might be devastating to the survival of sharks, he said. It was important for the government to keep data in such areas as transient shark population up to date.

    Trent said often most Chinese diners did not realize the delicacy they were eating was made from shark fins.

    In China, shark fin soup is usually served at banquets to impress guests. Some Chinese think dishes of shark fin, literally translated as "yu chi" or fish fin in Chinese, were made from domestic fish or were simply highly nutritional.

    Trent said consumers should find alternatives for shark fins and urged wasteful fishermen to harvest the whole of the shark instead of taking only the fins and discarding the rest.

    According to a 2009 Wild Aid report, the collapse and possible extinction of sharks would cause widespread ecological disruption with ensuing massive economic losses and decreased food security.

    Over-fishing, wasteful and destructive fishing practices and increasing demand for shark fin were blamed as the leading causes threatening the existence of sharks, the report said.

    More than 100 million sharks are killed every year, most of them only for their fins. The population of sharks has declined 80 percent during the past 50 years because of over-fishing.

    Shark fin is among the most expensive seafood products in the world, with prices reaching more than 700 U.S. dollars per kilo. The annual world trade is estimated to exceed 10,000 tonnes. China is the largest importer, accounting for half of the world market, says Wild Aid.

    Trent also called on China's government to promote international cooperation on shark conservation and management.

    Li Yanliang, deputy general director of the Aquatic Wild Fauna and Flora Administrative Office of the Ministry of Agriculture, said in January China's hunting of sharks, and their import and export was conducted strictly in accordance with international law.

    He said the government encouraged a "rational and sustained" development of fishery resources and the overall use of sharks, and had banned the part use of sharks.

    In addition, China was considering listing certain endangered sharks as protected, Li said.

    Since 2007, Wild Aid has carried out a series of shark-protection campaigns in China, attracting sports celebrities such as Yao Ming, Kong Linghui and Zhang Yining to appear in non-profit advertisements.